Facebook today opened its new data center in Forest City, North Carolina. The company's second U.S. data center is already online and serving live user traffic.

The data center comprises of two buildings: Building 1 broke ground in November 2010 and opened today, while Building 2 is expected to open later this year. In the last 16 months, more than 1.2 million hours from nearly 2,000 people went into making the site what it is today.

Back in October 2011, Facebook formed a foundation for the Open Compute Project (OCP) to drive more innovation and a greater focus on energy efficiency in the data center industry. The Forest City data center has a number of technical accomplishments at the facility that Facebook says it is proud of. Here are three the company wanted to highlight:

Forest City is the first major deployment of the v2 OCP web servers, which are in turn are some of the first to use Intel's Sandy Bridge processor in production.

Forest City is expected to join Facebook's facility in Prineville, Oregon, as one of the most energy efficient in the world, with a projected power utilization effectiveness (PuE) measurement for the entire facility of 1.06 to 1.08.

Forest City will be the first live test of the OCP's outdoor-air cooling designs in an environment where temperature and humidity conditions are considered to be outside the range of typical data center operations.

"Of course, our work here is by no means done. Right now, we're making great progress on a second building on the site that mirrors the first, and are on track to complete it in 2012," a Facebook spokesperson said in a statement. "We are also committed to keep evolving the technologies and designs at the facility, and are excited to be growing one of the world's most energy efficient data centers in your backyard."

The data center has its own Facebook Page, which at the time of writing already has over 10,000 Likes.